Paint sprayer



2 Sheets-'Sheet l A Ill PAINT SPRAYER W. G. ABBOTT, JR

Filed Nov. 23. 1923 Dec. 15, 1925- Deen l5, 4

w. G. ABBOTT, JR

PAI NT SPRAYER Filed Nov. 23, 1925 2 Sheets-Sheet 2 'I f iatted ned 15, 1925.

.PATENT oFFicE.

WILLIAM'G. ABBOTT, Jn., or wILroN, NEW HAMPSHIRE.

PAINT srBlAYEn.

./-t i l5 i Application illed November 23, 1923. Serial- No. 676,539;

. f. f To all 'whom' it mag/concern.' Be it Aknown'that I, WILLIAM G. ABBOTT, Jr., .af citizellof the United` States`- of America, and resident of Wilton,` in the .5 county of Hillsborough and State-fof New Hampshire'have invented new and usefullmprovements in Paint Sprayers, of which the following is a specification.

' his invention relates to liquid s raying 1Q devices, such as paint sprayers and t e like.

In the reduction of liquids to .a nely divided :spray, or so-called atomized condition, by means of the various spraying devices at present employed for this purpose,

' 15 numerous diiculties and limitations are encountered. Among others mayv be mentioned as. of outstanding importance, the clogging of the tubes throughwhich the liquid is supplied, the incomplete formation of a spray and the lack of control of thev liquid if it is too finely divided and forms a; mist. Present devices also involve the use of high pressures and are controlled solely hy varying the degrees of pressure used in, supplying the liquid yand air to the u atomizer, and such control is not reliable.

It` is accordinglyv an object of this invention to provide a device which will overcome vsuch diiiculties and which will control the rate and manner in which the liquid is sub-` divided and the direction of the spray-pro.- duced. It is a urther'object to avoid repeated adjustments during operation and to standardize vthe apparatus and its reuirements for liquid and air supply. ther objects ofthe invention will appear from the `following disclosure.

The invention comprises a device vin which a relatively rapid but lowressure stream' of gas .such as compresse airi is `provided, into which a second stream of gas at-lowe`r pressure, such as atmospheric .air, is allowed to enter upon the well-known .Bunsen burner,principle and ajet of thei 5 fluid to be divided or admit/ ed is introduced into the vcombined stream of gas, in the same direction and ly thereof.

The invention also includes the-independent control of the air streams, anda conpreferably concentricaltinued regulation of the. liquid jet corresponding to its particular characteristics and the type of spray desired. Other important features of theinvenpractical application, and is illustrated by the accompanying drawings:

Fig. 1 is an end view of a multiple tube sprayer:

Fig. 2 is a vertical longitudinal section on the line 2 2 of Fig; 1:

Fig. 3 1s a sectlon on Fig. 2:

Fig. 4 is the same as Fig-2 with the paint l supply valves in open position:

, Flg. 5 1s a vertlcal section and rear end `view of the sprayer:

Fig. 6'is a section on the line 6-6 ofy Fig. 2:'and I Fig. 7 is a section 011 the line 7-7 of Fig. 2.

Referring fto Fig. 2, the device shown consists of a ipeA 1, connected at one end to a source o compressed air through the stop cock 2, pipes 30 connected to a supply of paint under pressure, and discharge tubes 42 through which the spray of paint may be directed.- Pipes 1 and 30`serve as a handle for the sprayer.

At its'upper end-tube 1 expands into a triangular chamber 3 (see Fig. 7) havlng parallel Walls 4 and 5. Passing through the Wall 4 are three openings 6,y 7, 8, evenl y spaced apart. Each of said openings 1s adapted to receive one end of a threaded tube or nipple 12, its opposite end being closed by an annulardisc 13 having orices 14'therein and a" central opening in which is fixed a smaller tube 16 concentric with tube 12. Between tube 12` and tube 16 there is thus formed an annular passage 17 having the apertures 14 leading from it at an 23 formedin the plate 19 which is -fastened to the outer side of the wall 5 by screws 18 passing through the wall 4. Into 4each o ening there is tapped a hollow b I throng threaded-at one end 27 and formed into .a valve 31 at' 'theothen Rear-v v24 1 aving' a passageway 26 there- 65, the line 3-5 of wardly of said bushing is a second hollow bushing 28 tapped therein and serving as a sleeve for a needle valve 29, extending therethrough. A fluid supply pipe or duct 30 leads into each of theopenin'gs at a point intermediate said' bushings and lies parallel to the compressed air pipe or duct 1, being secured thereto by a collar 32.

The three needle valves 29 are mounted at their outer ends on triangular spider 33, and a rod 34 which is fixed upon the center of the spider passes through the plate 19, through bushing 36 in walls 5 and 4, and connectsy at its opposite end with a ring 37 pivoted to the free end of a lever 35 which is pivoted at its opposite end to the collar 32 on ythe handle. A catch 38 engages one end of a spring 39, the other end of which is fastened to lever 35, and is also adapted to engage .the lug 4l upon said lever.

A small tube or nozzle 42 of suclrexterior diameter as to just pass through the inner tube 16 is inserted therein and threaded into the end 27 ofthe corresponding bushing 24 on the opposite side of chamber 3, thus connecting with passageway 26 therein.

Tightly fitting over the projecting ends of each tube 12 there is provided an open tube 44, which has an annular row of holes 46 therein adjacent its connection with said tube 12. 'Ihe tube 44 projects beyond the outlet end of tube 42, and forms a comparatively wide annular space.47 therebetween. Surrounding triangular plate or head 19 and covering spider 33 isprovided a casing 48.

In operating the device for spraying paint a current of air is supplied to the apparatus through stop cock 2 in regulated amount and a stream of paint or other liquid is supplied through one or more of the tubes 30, as desired.

The current of air passes up through tube 1, through chamber 3, through annular. passage 17 and out through the orifices 14.4 In passing through apertures 14 the air streams tend to continue parallel with the tube, and in passing by the holes 46 create a partial vacuum or suction therethrough, thus drawing in a greatly fincreased volume of air. The combined currents pass through the annularopening 47, by the end of tube 42, and thence out of tube 44. 4

The paint or other liquid which is to be sprayed is supplied through tubes 30, and may be under low or high pressure as desired. It is preferably free from lumps, but the fine state of sub-division ordinarily required in such apparatus is not essential to successful operation. l

By grasping as a handle. the pipes 1 and 30 and lever 35, the latter is pressed inwardly forcing back ring 37,' rod 34 and spider 33, thus drawing needle valves 29 from their lvalve seats 31. This permits the fluid to flow through pipe 30, passage 26, tube 42, and out through the tube 44. I-Iere it encounters the combined currents of gas or air from apertures 14 and through the holes 46 which, on account of their greater speed, flick the liquid stream away from its outletand divide it into a spray of minute droplets or into a stream of relatively large globules as desired and as determined by the conditions provided. In passing through Vpipe 44 this spray is confined so that the In using materials having low viscosity a tube 42 will be selected which has a small 4 passageway or capillary. If the fluid has extremely high capillarity the length of tube 42 may be also be advantageously increased.4 The decrease of the bore and increase in length of the tube will effectively reduce the rate of flow of such fluids. On the other hand, if the paint is heavy or contains sizabley particles of solid pigments a tube 42 having a large bore will be employed. In such cases, tube 42 may also be shortened in length.- The resistance to flow is thereby diminished, and the rate at which the paint leaves the tube will be accordingly increased. To provide such variations a series of tubes 42 will bey used having equal outside diameters, but of varying internal dimensions and lengths to correspond with the characteristics of the various luids and other conditions of oper' ation (such as air pressure available, temperature ranges, etc.).

It will be apparent that this invention 4provides a device which is adaptable to ing or oxidation of the fluid, is overcomeby the accumulated effect of the pressure under which it is supplied. Owing to the uniform and relatively large passageways ei'ectiveness with which the air current contacts with the jet of liquid. A mist may be produced if desired, but it will be surrounded and directed by the annular stream of air, which restrains it from promiscuous scattering and the formation of floating mists.

By proper selection of the length and bore of the supply tubes employed and preliminary adjustment of j the pressure upon the air and liquid supply, further regulation is not necessary so long as the same liquid is being used and the same type of spray is desired.

In order to vary the de the spray the distance between the outlet ends of tubes 42 and 44 may be varied, the spread increasing asthe distance decreases.

This variation is preferably effected by,

varying the length of tube 44 as, for example, interchanging the tube with a tube of dilferent length.

Among the advantages incident to a plurality of nozzles grouped together is the advantageof separately spraying different liquids and then mixing the sprays. For example, in spotting terra cotta and other Wares different colors may be sup-plied to the respective nozzles thereby affording unique decorative effects.

l. Apparatus for spraying paint comprising an air nozzle having a cylindrical bore, a paint nozzle extending axially through said bore and terminating at a point substantially in rear of the forward end of said air nozzle, and supporting means for said nozzles whereby one nozzle may bc removed independently of the other, said air nozzle having an opening remote from the outer end of said paint nozzle to permit atmospheric air to be drawn through the air nozzle by the stream of air 4flowing therethrough.

2. Apparatus for spraying paint or the like comprising an approximately cylindriof spread of,

cal air nozzle, means for flowing a stream of air through the nozzle, and means for introducing paint under pressure into the said stream at a point near the center of the stream and remote from the forward end ofthe nozzle, said air nozzle having an opening in the rear of said point to admit air under atmospheric pressure. i

3. Apparatus for spraying paint or the like comprising an air nozzle, a paint nozzle extending along the axis'of the air nozzle in the rearward end thereof, means for flowing a stream of air through said air nozzle, a pressure tank and connections from the tank to the paint nozzle for feeding vpaint under pressure into said stream, said air nozzle having openings distributed around said paint nozzle to admit air under lower pressure.

4. A paint spraying device or the like, comprising a tube having a closed end, an annular row of air inlets disposed in the closed end, a 'fluid supply nozzle mounted concentrically in the closed end and projecting into'the tube, and apertures in the tube intermediate the air inlets and the outlet of said nozzle.

5. A paint spraying device or the like comprising a tube having a closed end, an

annular row of orifices disposed in said closed end and connected with a source of compressed air and a nozzle connected with a supply of fluid under pressure", mounted in the closed end of said tube and' projecting concentrically thereinto.

6. A paint sprayer device or the like, comprising a tube having one end closed, an annular 'row of orilices disposed in said closed end and connected with a source of compressed air, anozzle mounted in the closed end projecting concentrically into the tube and connected with a supply of paint under pressure, and apertures in said tube 4intermediate the closed end thereof andthe projecting end of. said nozzle.

7. Apparatus for spraying paint and the like comprising Va tube having a closed end, a plurality of air inlets being disposed in said closed end, a fluid supply nozzle projecting into said tube substantially in rear of the outer end thereof and detachably supported in said closed end so that the nozzle may be removed from the outer end of said tube, and apertures in Athe tube intermediate the air inlets and the outlet of said nozzles.

Signed by me at Wilton, N. H., this twentieth day of November, 1923.

' WILLIAM G. ABBOTT, JR. 

